中文摘要：

Internet逐渐成为通信基础设施,而BGP协议通过触发缓慢的反应式收敛过程应对网络拓扑和策略的变化,大量测量表明收敛过程中瞬时不可达以及环路造成很高的报文丢失率,难以支持延迟、中断敏感的应用.BAR-BGP采用了将预获取备份地址与反应式动态计算路径结合的方法以应对瞬时失效带来的转发中断.通告备份AS以较低的开销获得瞬时失效后可将报文封装转发到可行中继节点;在收敛过程中使用＂失效根源＂信息消除环路;并当无备份AS可用时,采用恢复转发模式进一步降低转发中断.通过使用Internet-like拓扑模拟实验证明了BAR-BGP有效避免收敛过程的瞬时失效与转发中断,增强网络可靠性.

英文摘要：

Internet is increasingly becoming a critical information infrastructure where even transient failure causes undesirable damages. BGP, the de facto standard routing protocol, is well known to suffer slow and reactive convergence process to follow the dynamic changes in the network topology and policy changes such as link or node failures. Many measurements show that BGP experiences the frequent loss of connectivity and routing loop during the routing re-convergence periods, which degrades the forwarding performance of data plane and so it is hard to support mission critical application. In this paper, we present a lightweight BAR-BGP protocol for achieving fast recovery from the failures of interdomain link failure, which deals with transient failure by combining the method of backup AS advertisement and reactive re-computing feasible paths. BAR-BGP provides a feasible relay forwarding of AS node which can be used to encapsulate packets to relay AS node immediately in case of AS node experiencing transient failure through advertising backup AS with very low message and storage overhead. It uses ＂root cause notification＂ to prevent routing loops during convergence. Furthermore, BAR-BGP uses recovery forwarding mode to improve the loss of connectivity in case that backup AS addresses are not available. Through the detailed simulation on Internet-like topology, we suggest that BAR-BGP improves Internet reliability, reduces the transient failure and forwarding disruption effectively during the routing convergence periods.